I'm in the process of trying to get perfect links on everyone I can. I have a habit of walling off my opponent into one kingdom and that's the ice one...and I'm too stubborn to let them take another kingdom so no perfect links with ice 'mon for me. :/

That is a great strategy. I used this to give myself a few in-game years to raise money and develop my parks so that evolved pokemon would show up.

Also, If you want great EXP, Leave a castle empty and let them take it, then take it back, then leave it empty again. Choose a castle that you like playing over and over.